The object of the invention is a lifting device for transportation in a horizontal position of flasks having a pair of lateral trunnions at either end, particularly flasks for the transportation of radioactive materials in industrial nuclear plants. The device consists of a crane hook attachment structure on top of a torsion body having crossbars on its ends with lug side arms for detachable engagement with the trunnions of the flask hanging from the ends of the crossbars.
Lifting devices to handle flasks are known to be employed for the removal of nuclear fuels from nuclear power plants, particularly flasks for the transportation of fuel elements, in a horizontal position.
To this end lifting devices are used which are constructed specially for one or two types of flasks of similar design. These lifting devices consist essentially of a crane hook attachment structure on top of a torsion body which has crossbars provided with lug side arms to engage the trunnions of the flask. These lifting devices are essentially characterized by having four lug side arms which are spreadable by means of hydraulic pumps in order to attach them to the flask trunnions, generally numbering four.
With these lifting devices flasks with different trunnion distances can indeed be handled, but before a different flask can be handled, mechanical adjustments must be made in the device. Likewise, there are flasks of different geometries, weights and specific shock absorber design which cannot be handled without an adjustment in the lifting device because the position of the centre of gravity of these devices cannot be adjusted continuously and handling of flasks can therefore only take place by exchanging the lug side arms of the device.
Therefore it is in many cases necessary to remove and replace the heavy lug side arms with the main crane employed in order to attain a correct attachment of the lug side arms to the flask.
In special cases the horizontal transportation of flasks is carried out by means of shackles and cables, which, however, has the disadvantage that it does not meet the latest safety standards.
Thus there is described in German OS No. 2528532 a device for securing loads on cranes with a redundantly arranged hanging cable, which, however, no longer meets present safety requirements.
Furthermore, there are lifting devices in use whose lug side arm elements indeed have two degrees of freedom of movement, but where the second one of these is only for the purpose of attaching the brackets to the flask trunnions.
It is likewise known (German OS No. 2,637,843) to design lifting devices with additional equipment for security against dropping the flask. In so doing a very expensive construction is involved, which must be provided in addition to the lifting device and which only secures the flask in a vertical position. However, there is no security for transportation of the flask in its horizontal position.
German OS No. 2,364,928 describes how all kinds of loads can be handled in a specified inclined position. Lifting devices of this type, however, on account of their size, cannot be operated in the airlocks of an industrial nuclear plant. Furthermore, with these types of lifting devices, no precautions are provided to guarantee the unconditionally required stability in the event of a lug side arm.
Therefore, it was the purpose of the invention to develop a lifting device for the transportation in a horizontal position of flasks provided with lateral trunnions at their ends, particularly transportation of flasks containing radioactive materials. Such a device consists essentially of a crane hook attachment structure on top of a torsion body having crossbars at its ends with lug side arms to be fitted to the trunnions of the flask hanging from the ends of the crossbars. This lifting device is usable without modification or adjustment for flasks having different centres of gravity; it does not give rise to a dropping risk in case of failure of a lug side arm; and, furthermore, guarantees ease of operation in the narrow airlocks of industrial nuclear plants.